1. Field of the Invention
The present invention generally relates to stairway structures. More particularly, the present invention relates to prefabricated concrete steps and stairway systems.
2. Description of the Related Art
It is well known in the art of construction to use concrete in the construction of stairs and stairways. Concrete is often used as a building material because it is durable and satisfactorily withstands public usage. Further, it is known to form a staircase with a plurality of pans rigidly attached between a pair of stringers, and to then pour concrete into the pans to cure therein to form the treads for the individual steps. An example of such pan-stringer construction is U.S. Pat. No. 4,838,005 to Graham et al.
The use of the pan between the stringers has shortcomings in that water can seep between the concrete and the pan and cause rust to the pan, which requires repair. Additionally, the concrete expands and contracts within the pan when subjected to significant temperature gradients, thus causing the pan to warp and the concrete tread to become unstable. Moreover, the concrete must be poured within the pans once the pans are in place on the stringers in order to properly form the staircase, adding to construction costs and time requirements at the job site.
Prefabricated stair systems are also known in the art, examples being U.S. Pat. Nos. 4,995,205 to Bennett; U.S. Pat. No. 5,203,128 to Bennett; and U.S. Pat. No. 3,981,112 to Dake. These patents illustrate various prefabricated and precast stairs and stair systems for installation into dwellings whereby stringers are put between various levels which are desired to be traversed by the staircase, and then precast steps are installed within the stringer to form the staircase. Various methods are used to attach the individual steps to the stringers to form the staircase, such as bolting the individual stairs to the stringers as in the Bennett '128 and Dake patents, or resting the precast stairs upon the stringers prior to fastening the stairs to the stringers, as shown in the Bennett '205 patent.
There are problems and shortcomings in the prior art of precast steps and stair systems, which neither the above nor any other reference known to the inventor fully addresses. It is accordingly to the provision of a precast concrete step and stairway system that addresses and solves the problems and shortcomings of the prior art that the present invention is primarily directed.